Phono cables

I used a audioquest Jupiter ground goody.  resolved all my hums from turntable and sub.

Tightening the L RCA connector was the key, I’d bet. Often the ground connection is made through the collar of the RCA jack. But why did you have hum only with stylus in groove? An unsolved mystery.

Nothing beats taking care of the basics 👍👍

 I replaced a grounding wire I ran from the bottom of the spindle under the TT to the grounding lug on the tone arm junction box (probably some 12 years old- the copper strands were badly oxidized) and I cleaned all the connections at the junction box. Also, I noticed the left rca connector on the junction box was loose, so so I tightened that up as well. No more hum with any of my IC's. Thanks for all your recommendations. Looking forward to trying some different cables now.

Does the hum change in intensity as the stylus traverses the LP surface? Is it loudest on the inner grooves?

For phono cables, I suggest the high level AntiCables, made in Minnesota. You can custom order them any way you want. Superb sound.

For that particular turntable I would look at Hijiri cables - take a read of 

https://forum.audiogon.com/discussions/hijiri-users-thread-2

I believe the name of the distributor is on there.

Or - if they're too pricey for you take a look at Zavfino products - like THE FUSION - SOLID PURE SILVER & OCC COPPER 

https://zavfinousa.com/collections/audio-interconnects/products/the-fusion-solid-pure-silver-occ-copper-hybrid-rca

Hope that helps - Steve

@lewm  Dynavector xx2 mkII on a VPI Aries table and VPI arm. 

What cartridge? What turntable? Some cartridges interact with EMI from some TT motors, which is one of the only ways I can think of to have hum only when the stylus is in the grooves.

I don't understand why you don't just use the Aural Thrills patch cords, quit obsessing and instead kick back and enjoy the music.

Hum is typically a ground loop or lack of ground... and could possibly be a bad RCA or ???...

I would first check all cables... make sure they are fully inserted to the receptacle. This includes 120v, RCA, etc. AND... the ground from the TT to the phono preamp (or preamp, if phono is built in) Also, check the tiny wires from tonearm.

If hum is still present... change RCA cables one at a time. You may have a bad solder joint or broken ground conductor.

As a last resort.. (in my opinion) you can try ungrounded 120v cables on grounded equipment.